A common goal of cover crops is to help suppress weeds that can compete with cash crops for resources. But if a cover crop comes back or continues to grow when it is not wanted, they can create the same challenge.
Volunteer cover crops, or cover crops emerging and growing in a field when not wanted, can be considered weeds and occur when the planned cover crop is not fully terminated, produces viable seed, or contains hard seed at planting.Improper Termination
Farmers must select termination methods and timing that work with their comfort level, goals, cover crop species, growth stage, and weather conditions. Ensuring a complete kill of a cover crop will ensure no continued growth and resource competition with the following cash crop.Cover crops that are allowed to mature to the point where they produce viable seed can contribute to the seed bank. Terminating before this growth stage can prevent these seeds from emerging when they are not desired.Hard Seed
Hard seeds have an impermeable coat that prevents water absorption. This can delay germination and allow the seed to remain in the soil, contributing to the seed bank. These seeds can then germinate and emerge when not intended. Certain clovers and vetch are often associated with hard seeds.Conclusion
Volunteer cover crops can negatively impact cash crops through resource competition. They can create added costs for farmers who must apply additional termination applications to manage them. Researching each species' ease, methods, and timing of termination will help ensure they do not escape and create issues later.References
- Crop Protection Network. (2024, April 1). When cover crops become weeds [Video]. YouTube. https://www.youtube.com/watch?v=wpygPkdXMgQ
